reckon_db_snapshots (reckon_db v3.1.1)

Snapshots API facade for reckon-db

Provides the public API for snapshot operations: - save: Save aggregate state as a snapshot - load: Load the latest snapshot for a stream - load_at: Load a specific snapshot version - list: List all snapshots for a stream - delete: Delete snapshots for a stream - exists: Check if a snapshot exists

Snapshots are used to optimize event replay by storing aggregate state at specific versions.

Summary

Types

snapshot/0

snapshot_data/0

snapshot_metadata/0

Functions

delete(StoreId, StreamId)

Delete all snapshots for a stream

delete_at(StoreId, StreamId, Version)

Delete a specific snapshot version

exists(StoreId, StreamId)

Check if any snapshot exists for a stream

exists_at(StoreId, StreamId, Version)

Check if a specific snapshot version exists

list(StoreId, StreamId)

List all snapshots for a stream

load(StoreId, StreamId)

Load the latest snapshot for a stream.

load_at(StoreId, StreamId, Version)

Load a specific snapshot version.

save(StoreId, StreamId, Version, Data)

Save a snapshot with default empty metadata

save(StoreId, StreamId, Version, Data, Metadata)

Save a snapshot with metadata

Types

snapshot/0

-type snapshot() ::
          #snapshot{stream_id :: binary(),
                    version :: non_neg_integer(),
                    data :: map() | binary(),
                    metadata :: map(),
                    timestamp :: integer(),
                    anchor_hash :: binary() | undefined,
                    mac :: {KeyId :: non_neg_integer(), MacBytes :: binary()} | undefined}.

snapshot_data/0

-type snapshot_data() :: map() | binary().

snapshot_metadata/0

-type snapshot_metadata() :: map().

Functions

delete(StoreId, StreamId)

-spec delete(atom(), binary()) -> ok | {error, term()}.

Delete all snapshots for a stream

delete_at(StoreId, StreamId, Version)

-spec delete_at(atom(), binary(), non_neg_integer()) -> ok | {error, term()}.

Delete a specific snapshot version

exists(StoreId, StreamId)

-spec exists(atom(), binary()) -> boolean().

Check if any snapshot exists for a stream

exists_at(StoreId, StreamId, Version)

-spec exists_at(atom(), binary(), non_neg_integer()) -> boolean().

Check if a specific snapshot version exists

list(StoreId, StreamId)

-spec list(atom(), binary()) -> {ok, [snapshot()]} | {error, term()}.

List all snapshots for a stream

load(StoreId, StreamId)

-spec load(atom(), binary()) -> {ok, snapshot()} | {error, not_found} | {error, term()}.

Load the latest snapshot for a stream.

Returns {ok, Snapshot} if found and integrity-valid. Returns {error, not_found} if no snapshot exists. Returns {error, {integrity_violation, _}} if the store has integrity enabled and the loaded snapshot fails verification. Callers (typically aggregate rebuild) should treat an integrity violation as a directive to fall back to full event replay from the stream's chain_start_version watermark.

load_at(StoreId, StreamId, Version)

-spec load_at(atom(), binary(), non_neg_integer()) ->
                 {ok, snapshot()} | {error, not_found} | {error, term()}.

Load a specific snapshot version.

Same verification semantics as load/2.

save(StoreId, StreamId, Version, Data)

-spec save(atom(), binary(), non_neg_integer(), snapshot_data()) -> ok | {error, term()}.

Save a snapshot with default empty metadata

Parameters: StoreId - The store identifier StreamId - The stream this snapshot belongs to Version - The event version this snapshot represents Data - The aggregate state to snapshot

Returns ok on success or {error, Reason} on failure.

save(StoreId, StreamId, Version, Data, Metadata)

-spec save(atom(), binary(), non_neg_integer(), snapshot_data(), snapshot_metadata()) ->
              ok | {error, term()}.

Save a snapshot with metadata